Crescent Moon and Earthshine The thin crescent moon sets over ESO's Paranal Observatory in Chile. The crescent is clearly visible, but you can also see the rest of the moon very faintly, because of the phenomenon known as earthshine. Sunlight bouncing off the Earth illuminates the surface of the moon. This image was captured Oct. 27, 2011. Mercury and Venus are there, too, by the way. ESO/B. Tafreshi/TWAN
Remote Aliens Could Detect Life On Earth By Looking At The Moon -- Popular Science
New detection method could help spot signs of life on exoplanets.
So many exoplanets may hold water, atmospheres, just-right temperatures and a rocky surface for life to flourish — we just need to know where to look. Once astronomers have pinpointed a good candidate, we also need to know how to look — which instruments and methods might sniff out the right chemical signatures of life. A new trick that essentially amplifies those signatures could be one way to do it. Astronomers at the European Southern Observatory just discovered life on Earth with this method, treating our home as if it were an exoplanet.
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